What is the best way to marble a cake chocolate and vanilla?

Crystal
- from Paragould, AR

Prepare your yellow cake mix following package instructions. Remove about 1 cup of batter; pour remaining batter into your prepared pans. Stir 1 oz. melted semi-sweet chocolate into the reserved 1 cup batter. Place spoonfuls of the chocolate batter randomly over the yellow batter in the pans. For deep pans, gently fold the chocolate batter down into the yellow batter; for 2- or 3-in. deep baking pans, take a knife and gently run it through the batter for a marble effect.